Hydrocephalus is a disorder that affects foals during gestation. The foal develops a deformed and distended skull due to a build-up of cerebrospinal fluid around the brain. Foals with hydrocephalus are often stillborn and the birth can be very difficult due to the abnormal size and shape of the foal's head.
Hydrocephalus occurs when the drainage of cerebrospinal fluid down the spine is blocked. This can be caused by abnormal bone growth (as is the case for genetic hydrocephalus) or by one-off events such as blood clots blocking the outlet.
Hydrocephalus is an autosomal recessive disorder. Autosomal disorders are equally likely to affect male or female horses, while "recessive" means that a horse needs to inherit the hydrocephalus mutation from both its sire and its dam to be affected.
Gene or region and technical reference
Gene: B3GALNT2 (causative). Reference: Ducro et al. (2015)
n. Test developed using manufactured DNA, animal controls.
HYD. Test developed using manufactured DNA, animal cases.